Various types of vehicle door latches and handles have been developed. The latch and handle assembly may include a handle that can be pulled outwardly by a user to release a door latch, thereby permitting the door to open. However, if a vehicle is subject to a lateral acceleration, the acceleration may cause the handle to shift outwardly due to its own mass, thereby causing the latch to release. Various counterweights and inertia locks have been developed to prevent inadvertent unlatching of a door latch during lateral acceleration of the vehicle.
With reference to FIGS. 1 and 2, a prior art latch release mechanism 5 includes an outside release lever 6 having an end 8 that is operably connected to an outside door handle (not shown) of a motor vehicle. An intermediate link 10 is pivotably connected to outside release lever 6 at a pin or pivot 12, such that rotation of outside release lever 6 from a rest position to an actuated position causes link 10 to shift longitudinally as indicated by the arrow “A.” End 14 of link 10 includes a step or notch 16 having a push surface 18 that is configured to engage a surface 20 of a pawl lifter 22. Pawl lifter 22 is rotatably connected to a door structure by a rotatable connector 24 which may comprise a boss, pin, shaft, or the like for movement. Link 10 is rotatably biased into engagement with pawl lifter 22 by a torsion spring (not shown) at pivot 12. The torsion spring biases link 10 in a counter clockwise direction (FIGS. 1 and 2), such that longitudinally extending surface 26 of link 10 slidably engages end surface 28 of pawl lifter 22 as link 10 moves in the direction of the arrow “A.” Thus, in operation, surface 26 of link 10 always remains engaged with the end surface 28 of pawl lifter 22, regardless of the position and velocity of link 10. If an exterior force tending to rotate outside release lever 6 in the direction of the arrow A1 is applied to an outside door handle, link 10 shifts longitudinally in the direction of the arrow A with surfaces 26 and 28 slidably engaging each other initially. Surfaces 18 and 20 come into contact and abuttingly engage one another to thereby rotate pawl lifter 22 in the direction of the arrow “A2” from its unlatched position to its latched position. Thus, in operation, movement of outside release lever 6 from its rest position to its actuated position always causes surface 18 of link 10 to contact surface 20 of pawl lifter 22 and always unlatches the vehicle door latch, regardless of the velocity at which outside release lever 6 is moved from its rest position to its actuated position. The pawl (not shown) is directly connected to pawl lifter 22, such that rotation of pawl lifter 22 from its unlocked position to its locked position causes the pawl to shift from the latched position to the unlatched position, thereby unlatching the vehicle door latch.